Pros
Probably the best thing about SSE is that you will most certainly have the chance to take on the challenges at work if you so wish. The pay is not bad at all and the people there are generally nice. If you are looking for a place to tread water or if you are not really bothered about getting on too soon, then definitely work there! You can opt into a pension, shares as well but generally speaking it is no better an offer than othr similar sized companies.
Cons
Too many promises! On starting with SSE take a look at their corporate inspired website/intranet. The offer and promise of training and development seem right on! The problem is delivery. Unfortunately there is a gap between the corporate wishful thinking and the hard day-to-day reality of having no time to develop in the way that is promoted. You will not be given time to 'find the carreer you want' at SSE. Its just the same as any other bog standard employer expecting you to go off and spend all your own time developing yourself, putting this into the workplace and there being no substansive payoff for this after an extended time.